what's a blogmark?

I can't figure out the difference between a weblink and a blogmark.

Plus, my site users see the "Blogmark" link on the create content page, and they think this is the link to create a blog post, becuase there is no help text.

I had to remove the blogmark node type in weblink.module to make that confusing link go away.

But what the heck is blogmark there for? Why not just have weblinks?